I believe it is a V-max bullet not an SST. The v-max is a varmint bullet with a thin jacket designed to disrupt at impact (SST's are designed for game). If your gun has a fast twist you may be disrupting the intergrety of the bullet in flight (although doubt full in .222) with the thinner jacket.

In all my rifles the v-max has been nearly if not AS good as match grade bullets. They are normally know as VERY accurate bullets. There could be an issue with your barrel (causing deformation to the bullets), or the gun just might not like them??? If you don't like them, I'd be happy to take them off your hands.

Good luck!